It is to be noted that a “starting device” means both a starting block device for athletics and a starting platform or block for swimming or another sport. This starting device must allow the competitor's response time to be determined, particularly following the start signal of the competition, and must also indicate any false start.
Currently, a starting device, such as a starting block device, may include, on the base structure, a detection means for determining a competitor's response time at the start of an athletics race. This detection means is generally formed of a sensor placed, for example, on a block for a runner's foot. The sensor may be a simple electric switch which is closed when sufficient force is applied to the block when the competitor pushes off at the start, and which is greater than a determined threshold. This involves an inconvenient backward movement of the block, which, moreover, is not unidirectional. Further, the sensor has to be adjusted according to the type of race and the competitors who are competing. A competitor may also apply a sufficient constant force to the block to close the sensor switch as he gets into position prior to the start. This prevents the response time from being precisely measured when the start signal for the race is given. This constitutes several drawbacks for this type of starting block.
U.S. Pat. No. 5,467,652 discloses a starting block device for an athletics race. This starting block device includes a longitudinal bar for anchorage to the ground, on which are placed a first foot block and a second foot block respectively on each side of the bar. The blocks can be moved along the length of the bar, guided in lateral grooves in the bar and adjusted by pins inserted in one of the holes provided in the bar. Each block has a foot bearing surface which is angularly adjustable and covered with a pressure sensitive elastomer pad. These pressure pads are connected to a control and display module by electric cables. The pressure pad sensors are connected to amplifiers, which supply analogue output signals that vary according to the measured pressure. When the start signal of a race is given, the starting block device is capable of measuring, storing and displaying the pressure levels detected on each bearing surface. It can also determine the time that elapses between the start signal and the runner's start on the basis of the variation in pressure measured on the blocks so as to indicate any false start. However, the action of a runner's foot against one of the sensor pads does not occur in a single direction. This may lead to imprecision in the start time measurement, which constitutes a drawback. Moreover, nothing is provided to overcome any malfunction in each sensor.
WO Patent Application No. 99/32889 discloses a system for measuring the response time when a runner starts from a starting block device secured to the ground. The start time measurement is obtained via an accelerometer arranged on at least one starting block of the starting block device. The accelerometer is mounted on the starting block via a rigid coupling. A measured acceleration over time curve at the start of a race can be determined and displayed on a display screen. As in the preceding document, nothing is provided to guarantee a unidirectional movement of the block in order to measure the start time precisely. Moreover, the use of an accelerometer intrinsically means that a precise start time measurement cannot be obtained when the competitor pushes off, which is a drawback.